Assessment of Dried Pineapple By-products as a Bioactive Plant Material for Enhancing Dairy Productivity in Holstein Cows

Background: Agro-industrial by-products represent an important opportunity for sustainable livestock production. Pineapple (Ananas comosus) residues are rich in bromelain, polyphenols, and dietary fiber and are known for their antioxidant and anti-inflammatory activities. However, few studies have evaluated the effects of dried pineapple by-product powder (DPP) on dairy productivity and metabolic function.<br/>Methods and Results: A DPP feeding trial was conducted with 20 mid-lactation Holstein cows (90 ± 15 days old in milk; 620 ± 30 kg body weight). Cows were randomly assigned to two groups: a control group fed a basal total mixed ration (TMR) and a treatment, fed a TMR supplemented with 1% DPP (dry matter basis) for 4 weeks. Milk yield and composition were measured weekly, and blood samples were analyzed at weeks 0 and 8 for serum biochemical parameters including glucose, amylase, and lipase. Cows fed DPP showed a 6.3% increase in daily milk yield (p < 0.05) without significant changes in milk fat, protein, or lactose concentrations. The somatic cell count (SCC) decreased by 23% (p < 0.05), indicating improved udder health. Blood glucose concentrations decreased (p < 0.05), suggesting improved energy utilization for milk synthesis, without changes in amylase or lipase activity. Liver (aspartate aminotransferase and alanine aminotransferase) and kidney (creatinine) function remained within normal physiological limits. Based on the in vivo findings, the antioxidant, and anti-inflammatory activities of DPP were evaluated in vitro. The ABTS radical scavenging assay demonstrated strong antioxidant capacity (IC₅₀≈ 220 µg/mL), and the nitric oxide (NO) inhibition assay showed significant, dose-dependent suppression of NO production in LPS-stimulated RAW 264.7 macrophages (p < 0.01), confirming antioxidant and anti-inflammatory effects.<br/>Conclusions: DPP improved in vivo dairy performance by enhancing milk yield, reducing SCC, supporting efficient energy metabolism without adverse effects on liver or kidney function, and exhibiting potent in vitro antioxidant and anti-inflammatory properties. These findings highlight the potential of DPP as a sustainable and functional feed additive for dairy cows.